Methods for detection of failure and recovery in a radio link

ABSTRACT

A method, telecommunication apparatus, and electronic device for detecting a status of a radio link are disclosed. A transceiver  302  may maintain a radio link with a network base station  104.  A processor  304  may map channel state information to a synchronization status associated with the radio link based on the received signal and determine the synchronization status via a block error rate estimate in the radio link based on the channel state information.

FIELD OF THE INVENTION

The present invention relates to a method and system for maintaining adata link. The present invention further relates to determining if adata link is in synchronization.

INTRODUCTION

The Third Generation Partnership Project (3GPP) is developing a LongTerm Evolution (LTE) carrier using a physical layer based on globallyapplicable evolved universal terrestrial radio access (E-UTRA). A userequipment (UE) device may use a cell-specific reference signal as ametric to determine if a radio link is in synchronization or out ofsynchronization by determining whether reliable transmission of physicaldownlink control channel (PDCCH) code word with specific formats can besupported in the link.

SUMMARY OF THE INVENTION

A method, telecommunication apparatus, and electronic device fordetecting a status of a radio link are disclosed. A transceiver maymaintain a radio link with a network base station. A processor may mapchannel state information to a synchronization status associated withthe radio link based on the received signal and determine thesynchronization status via a block error rate estimate in the radio linkbased on the channel state information.

BRIEF DESCRIPTION OF THE DRAWINGS

Understanding that these drawings depict only typical embodiments of theinvention and are not therefore to be considered to be limiting of itsscope, the invention will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 illustrates one embodiment of a communication system.

FIG. 2 illustrates a possible configuration of a computing system to actas a base station.

FIG. 3 illustrates in a block diagram one embodiment of the userequipment.

FIG. 4 illustrates, in a flowchart, one embodiment of a method ofdetermining a synchronization event.

FIG. 5 illustrates, in a flowchart, one embodiment of a method ofdetermining whether a radio link is out of synchronization.

FIG. 6 illustrates, in a flowchart, one embodiment of a method ofdetermining whether a radio link is in synchronization.

DETAILED DESCRIPTION OF THE INVENTION

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. Thefeatures and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims. These and other features of the present inventionwill become more fully apparent from the following description andappended claims, or may be learned by the practice of the invention asset forth herein.

Various embodiments of the invention are discussed in detail below.While specific implementations are discussed, it should be understoodthat this is done for illustration purposes only. A person skilled inthe relevant art will recognize that other components and configurationsmay be used without parting from the spirit and scope of the invention.

The present invention comprises a variety of embodiments, such as amethod, an apparatus, and an electronic device, and other embodimentsthat relate to the basic concepts of the invention. The electronicdevice may be any manner of computer, mobile device, or wirelesscommunication device.

A method, telecommunication apparatus, and electronic device fordetecting a status of a radio link are disclosed. A transceiver maymaintain a radio link with a network base station. A processor may mapchannel state information to a synchronization status associated withthe radio link based on the received signal and determine thesynchronization status via a block error rate estimate in the radio linkbased on the channel state information.

FIG. 1 illustrates one embodiment of a communication system 100. Thecommunication system 100 may include a network 102, base station 104,and user equipment (UE) 106. Various communication devices may exchangedata or information through the network 102. The network 102 may be anevolved universal terrestrial radio access (E-UTRA), or other type oftelecommunication network. A network entity, such as the base station104, may assign a UE identifier (UEID) to the UE 106 when the UE 106first joins the network 102. For one embodiment, the base station 104may be a distributed set of servers in the network. The UE 106 may beone of several types of handheld or mobile devices, such as, a mobilephone, a laptop, or a personal digital assistant (PDA). For oneembodiment, the UE 106 may be a WiFi® capable device, a WiMax® capabledevice, or other wireless devices.

FIG. 2 illustrates a possible configuration of a computing system to actas a base station 104. The base station 104 may include acontroller/processor 210, a memory 220, a database interface 230, atransceiver 240, input/output (I/O) device interface 250, and a networkinterface 260, connected through bus 270. The base station 104 mayimplement any operating system, such as Microsoft Windows®, UNIX, orLINUX, for example. Client and server software may be written in anyprogramming language, such as C, C++, Java or Visual Basic, for example.The server software may run on an application framework, such as, forexample, a Java ® server or .NET ® framework

The controller/processor 210 may be any programmed processor known toone of skill in the art. However, the decision support method may alsobe implemented on a general-purpose or a special purpose computer, aprogrammed microprocessor or microcontroller, peripheral integratedcircuit elements, an application-specific integrated circuit or otherintegrated circuits, hardware/electronic logic circuits, such as adiscrete element circuit, a programmable logic device, such as aprogrammable logic array, field programmable gate-array, or the like. Ingeneral, any device or devices capable of implementing the decisionsupport method as described herein may be used to implement the decisionsupport system functions of this invention.

The memory 220 may include volatile and nonvolatile data storage,including one or more electrical, magnetic or optical memories such as arandom access memory (RAM), cache, hard drive, or other memory device.The memory may have a cache to speed access to specific data. The memory220 may also be connected to a compact disc-read only memory (CD-ROM),digital video disc-read only memory (DVD-ROM), DVD read write input,tape drive, or other removable memory device that allows media contentto be directly uploaded into the system.

Data may be stored in the memory or in a separate database. The databaseinterface 230 may be used by the controller/processor 210 to access thedatabase. The database may contain any formatting data to connect the UE106 to the network 102.

The transceiver 240 may create a data connection with the UE 106. Thetransceiver may create a physical downlink control channel (PDCCH) and aphysical uplink control channel (PUCCH) between the base station 104 andthe UE 106.

The I/O device interface 250 may be connected to one or more inputdevices that may include a keyboard, mouse, pen-operated touch screen ormonitor, voice-recognition device, or any other device that acceptsinput. The I/O device interface 250 may also be connected to one or moreoutput devices, such as a monitor, printer, disk drive, speakers, or anyother device provided to output data. The I/O device interface 250 mayreceive a data task or connection criteria from a network administrator.

The network connection interface 260 may be connected to a communicationdevice, modem, network interface card, a transceiver, or any otherdevice capable of transmitting and receiving signals from the network106. The network connection interface 260 may be used to connect aclient device to a network. The network connection interface 260 may beused to connect the teleconference device to the network connecting theuser to other users in the teleconference. The components of the basestation 104 may be connected via an electrical bus 270, for example, orlinked wirelessly.

Client software and databases may be accessed by thecontroller/processor 210 from memory 220, and may include, for example,database applications, word processing applications, as well ascomponents that embody the decision support functionality of the presentinvention. The base station 104 may implement any operating system, suchas Microsoft Windows®, LINUX, or UNIX, for example. Client and serversoftware may be written in any programming language, such as C, C++,Java or Visual Basic, for example. Although not required, the inventionis described, at least in part, in the general context ofcomputer-executable instructions, such as program modules, beingexecuted by the electronic device, such as a general purpose computer.Generally, program modules include routine programs, objects,components, data structures, etc. that perform particular tasks orimplement particular abstract data types. Moreover, those skilled in theart will appreciate that other embodiments of the invention may bepracticed in network computing environments with many types of computersystem configurations, including personal computers, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, and thelike.

FIG. 3 illustrates in a block diagram one embodiment of atelecommunication apparatus or electronic device to act as the UE 106.The UE 106 may be capable of accessing the information or data stored inthe network 102. For some embodiments of the present invention, the UE106 may also support one or more applications for performing variouscommunications with the network 102. The UE 106 may be a handhelddevice, such as, a mobile phone, a laptop, or a personal digitalassistant (PDA). For some embodiments of the present invention, the UE106 may be WiFi® capable device, which may be used to access the network102 for data or by voice using VOIP.

The UE 106 may include a transceiver 302, which is capable of sendingand receiving data over the network 102. The UE 106 may include aprocessor 304 that executes stored programs. The UE 106 may also includea volatile memory 306 and a non-volatile memory 308 which are used bythe processor 304. The UE 106 may include a user input interface 310that may comprise elements such as a keypad, display, touch screen, andthe like. The UE 106 may also include a user output device that maycomprise a display screen and an audio interface 312 that may compriseelements such as a microphone, earphone, and speaker. The UE 106 alsomay include a component interface 314 to which additional elements maybe attached, for example, a universal serial bus (USB) interface.Finally, the UE 106 may include a power supply 316.

A UE 106 may determine whether a radio link is in synchronization or outof synchronization with a base station by assuming the transmission of acontrol channel type with a specific format, subcarrier mapping,transmit antenna configuration, and power boost. The transmission formatmay correspond to a particular error correcting code type, such asconvolutional code, block code, turbo-code; payload size; code rate;block size; modulation type; or other error correcting code type. Thecontrol channel type need not be physically transmitted in the signal,and no actual decoding followed by cyclical redundancy check (CRC) maybe necessary to detect whether the radio link isout-of-synchronization/in-synchronization. The UE 106 may make thedetection by using an estimate of the channel state for a portion of thesubframe which contains the control channel, such as propagation channelcoefficients, interference variance, and others. The channel stateinformation may be estimated from cell-specific reference signals or byother methods. The channel state may be defined in generic terms as therealization of the propagation channel between the transmitter and thereceiver together with noise and interfering signals over thetime-frequency region of signal reception. As one example, channel statemay refer to the collection of the per-subcarrier channel coefficientsand the per-subcarrier interference plus noise variance statistics. Asanother example, channel state information may refer to theper-subcarrier signal to interference and noise ratio (SINR).

The UE 106 may estimate the block error rate (BLER) of a radio link todetermine if the link is usable, in failure, or in recovery. The SINR ofthe reference signal computed over the entire time-frequency resourcesin the control region may be used as an input to a channel statefunction describing channel state information. The channel stateinformation function may map all subband signal to noise ratio (SNR) andchannel quality information (CQI) type metrics. The channel stateinformation function may approximate reference signal SINR computed overthose resource element groups corresponding to the physical downlinkcontrol channel (PDCCH) codeword. The channel state information functionmay be a cascaded set of functions. In one embodiment, a firstsub-function may take the received signal as an input to calculate anestimate of the channel state, such as a channel coefficient estimatedper subcarrier and the interference and noise variance per subcarrier. Asecond sub-function may take the channel state estimate and map that tothe BLER estimate.

Different UE receiver implementations may have different PDCCHdemodulator or decoder capabilities. The BLER mappings for a UE 106 maybe adjusted to more accurately reflect the actual implementation.Alternately, a UE 106 may use pre-specified functions to obtain an“effective SINR” metric and for comparison against thresholds toidentify an out-of-synchronization or in-synchronization event. A UE 106may form mean mutual information per bit (MMIB) estimates or channelcapacity estimates instead of BLER to determine whether the link cansupport reliable transmissions of PDCCH.

The channel state information or BLER estimate may be obtained from eachsubframe sampled from the processing window in continuous receptionmode. For a discontinuous reception mode of operation, these subframesmay correspond to the subframes, or a subset thereof, at the pagingoccasions successively separated by a discontinuous cycle period. Theprocessing windows may correspond to multiple discontinuous receptionperiod durations from which the subframes are sampled.

The UE 106 may use the aggregated per-subband channel state informationfor the PDCCH codeword to obtain the BLER estimate. Since, the actualtime-frequency diversity experienced by the PDCCH codeword in thepropagation channel generates the BLER estimate, the estimate of BLERmay be more accurate. On the other hand, if the UE 106 uses a singlereference signal SINR level, compared against thresholds, fordetermination of the synchronization events, the wideband nature of thePDCCH codeword mapping and the associated gains due to frequencydiversity for higher bandwidths, such as greater than 1.4 MHz, may notbe captured. A synchronization event may be an event in which thesynchronization status of the radio link changes. This practice may leadto increased false triggers of out-of-synchronization events when thenarrowband reference signal SINR is low, such as when signal over themeasurement bandwidth is in fade, while the PDCCH codeword would havebeen decodable.

FIG. 4 illustrates, in a flowchart, one embodiment of a method 400 ofdetermining a synchronization event. The UE 106 may maintain a radiolink with a base station (Block 402). The UE 106 may monitor thesynchronization status associated with the radio link (Block 404). TheUE 106 may map channel state information to a synchronization status ofthe radio link based on the received signal over a specified bandwidth(Block 406). The UE 106 may determine the synchronization status via theBLER estimate in the radio link based on the channel state information(Block 408). The UE 106 may determine the synchronization event basedupon the BLER (Block 410).

The UE 106 may use different formats to determine when anout-of-synchronization event has occurred versus when anin-synchronization event has occurred. A first threshold, hereinreferred to as a failure threshold, may signify at which point a BLERbecomes high enough to indicate that a radio link has become out ofsynchronization. A second threshold, herein referred to as a recoverythreshold, may signify at which point a BLER becomes low enough toindicate that a radio link has become in synchronization. Both levelsmay be determined as a function of bandwidth, such as 1.4, 3, 5, 10, 15,20 MHz, and transmit antenna configuration, such as 1×2, 2×2 spacefrequency block coding (SFBC) or 4×2 SFBC-frequency switchingtransmission diversity (FSTD). Alternately, the UE 106 may use just twolevels, one for out-of-synchronization and one for in-synchronization,common across bandwidths and transmit antenna configuration.

An out-of-synchronization event may occur when the SNR drops or thechannel quality deteriorates such that the control or shared channelsbecome undecodable. The threshold may be determined by considering thebest coverage available when the maximum error protection, maximum powerboosting and maximum frequency-time diversity transmission are deployed.

The UE 106 may use reference signal symbols to obtain a per-subbandchannel state information for the control region of a subframe. Asubband may be one control channel element (CCE), resource elementgroup, or some other aggregation of subcarriers that contain the mappedsymbols of the PDCCH codeword. A PDCCH payload may have a specificformat, such as Format 1A. The format may have a specific minimumpayload size, such as 31 bits for 10 MHz; a specific maximum aggregationlevel applicable to the bandwidth, such as an aggregation level of 8 for10 MHz bandwidth; and a specific codeword-to-subcarrier mapping thatachieves the maximum time-frequency diversity. Alternately, the UE 106may use a typical payload size, typical aggregation level, and a typicalcodeword to subcarrier mapping. The UE 106 may use a maximum power boostrelative to the reference signal, such as +3 dB, or a typical powerboost relative to the reference signal, such as 0 dB.

The base station 104 need not actually transmit the PDCCH payload of theassumed type. The UE 106 may calculate the per-subband channel stateinformation for the subcarrier under the assumption that PDCCH payloadof the assumed type was transmitted. The UE 106 may use the per-subbandchannel state information for the entire PDCCH codeword for the assumedtype to obtain a BLER estimate for the PDCCH codeword. The UE 106 mayobtain the BLER estimate for each of the subframes in anout-of-synchronization processing interval, such as an interval of 200ms. The UE 106 may average these estimates over theout-of-synchronization processing duration.

To generalize this mapping, the UE 106 may define channel stateinformation that maps all the per-subband SINR or CQI-type metrics fromthe subframes to a single BLER estimate that is compared against athreshold for determination of the out-of-synchronization event. The UE106 may define a criterion for out-of-synchronization detection as anevent in which the average BLER estimate is greater than a setpercentage over the out-of-synchronization processing duration or theBLER estimate is greater than a set percentage for the last set numberof subframes.

In one example, the UE 106 may form BLER estimates for five subframesseparated by 40 ms in a 200 ms processing window for the purpose ofout-of-synchronization evaluation. For a subframe for which the PDCCHBLER is being estimated, the UE 106 may assume that a PDCCH Format 1Apayload of ˜42 bits (for 10 MHz operation) is being transmitted in thecontrol region on the first n (0<n<4) orthogonal frequency divisionmultiplexing (OFDM) symbols in the subframe, starting the first CCE inthe common search space at an aggregation level of 8. The UE 106 mayidentify the time-frequency resource element groups on which thecodeword gets mapped and calculates the reference signal SINR for thoseresource element groups. The reference signal SINR may be calculated bysignal interpolation, by a minimum mean square error channel and noiseestimator, or some other technique. For 72 resource element groups, theUE 106 may use 72 non-negative reference signal SINR terms in BLERestimation. The UE 106 may use the reference signal resources from thesame subframe for reference signal SINR estimation for the controlresource element groups, as well as current, past and future subframes.The channel state information that maps all the reference signal-SINRterms to a BLER value may be determined off-line and pre-stored in theUE 106. This function may map the 72 reference signal SINR terms to aBLER estimate value for the Format 1A PDCCH codeword. One example ofchannel state information may be a function that takes mean referencesignal SINR and the covariance of a reference signal SINR, capturing themean level and the time-frequency variation of the reference signalSINR, as input arguments and outputs a BLER value. The power boost valueassumed for the Format 1A PDCCH payload may be subsumed into the channelstate information. Alternately, the power boost may be added to thereference signal SINR terms to reflect the SINR corresponding to theresource element groups to which the PDCCH payload is mapped. The BLERestimates from the 5 subframes may then be averaged to compute anaverage BLER which is compared against a threshold, such as 10%, tocheck if the out-of-synchronization criterion is satisfied.

Out-of-synchronization determination may create a processing overheadrelative to the case when the out-of-synchronization event is determinedusing, for example, the narrowband reference signal SINR measure. Tocorrect for this, the UE 106 may subdivide the out-of-synchronizationprocessing window of into two parts. The UE 106 may continuously monitorthe narrowband reference signal received power (RSRP) averaged over theduration of the first part. Since the narrowband reference signal SINRmeasure somewhat correlates with the wideband CQI-type metric orper-subband SINR for the PDCCH resource elements, a synchronizationcheck threshold may be used to trigger BLER estimation. For example, ifthe narrowband reference signal SINR drops below the synchronizationthreshold chosen by the implementation by averaging reference signalSINR over the first part of the processing window, the second part mayuse the synchronization threshold to trigger the search for anout-of-synchronization event using the BLER mapping approach.

FIG. 5 illustrates, in a flowchart, one embodiment of a method 500 ofdetermining whether a radio link is out of synchronization. The UE 106may maintain a radio link with a base station (Block 502). If the RSRPis less than a synchronization check threshold (Block 504), the UE 106may map channel state information for the radio link based on thereceived signal over a specified bandwidth (Block 506). The UE 106 mayset the failure range based upon a payload parameter, such as a controlchannel type (Block 508). The control channel type may be a specifictransmission format, sub-carrier mapping, transmit antennaconfiguration, power boost, or other parameters. The transmission formatmay be an error correcting code type, payload size, code rate, blocksize, modulation type, or other formats. The error correcting code typemay be a convolution code, block code, turbo-code, or other codes. TheUE 106 may estimate a metric for the radio link based on the channelstate information using a format best suited for determining if theradio link failure is about to occur, or failure format (Block 510). Themetric may be a block error rate, a mean mutual information per bit,average signal to noise ratio, channel capacity, or other metric. If themetric is within the failure range (Block 512), the UE 106 may designatethe radio link as having an out of synchronization event (Block 514).

The UE 106 may use a different format for determining anin-synchronization event, with less overhead. The UE 106 may usereference signal symbols to obtain a per-subband channel stateinformation for the control region of a subframe. A subband may be onecontrol channel element (CCE), resource element group, or some otheraggregation of subcarriers that contain the mapped symbols of the PDCCHcodeword. A PDCCH payload may have a specific format, such as Format 1Aor 1C. The format may have a specific maximum payload size, such as 31bits for 10 MHz; a specific minimum aggregation level applicable to thebandwidth, such as an aggregation level of 2; and a specificcodeword-to-subcarrier mapping that achieves the minimum time-frequencydiversity. Alternately, the UE 106 may use a typical payload size,typical aggregation level, and a typical codeword to subcarrier mapping.The UE 106 may use a minimum power boost relative to the referencesignal, such as −6 dB, or a typical power boost relative to thereference signal, such as 0 dB.

The base station 104 need not actually transmit the PDCCH payload of theassumed type. The UE 106 may calculate the per-subband channel stateinformation for the subcarrier under the assumption that PDCCH payloadof the assumed type was transmitted. The UE 106 may use the per-subbandchannel state information for the entire PDCCH codeword for the assumedtype to obtain a BLER estimate for the PDCCH codeword. The UE 106 mayobtain the BLER estimate for each of the subframes in anin-synchronization processing interval, such as an interval of 100 ms.The UE 106 may average these estimates over the in-synchronizationprocessing duration.

To generalize this mapping, the UE 106 may define channel stateinformation that maps all the per-subband SINR or channel stateinformation-type metrics from the subframes to a single BLER estimatethat is compared against a threshold for determination of thein-synchronization event. The UE 106 may define a criterion forin-synchronization detection as an event in which the average BLERestimate is less than a set percentage over the in-synchronizationprocessing duration or the BLER estimate is less than a set percentagefor the last set number of subframes.

For in-synchronization evaluation, the UE 106 may use Format 1C, as thesystem information block (SIB), paging channel (PCH) and random accesschannel (RACH) response messages are addressed by this PDCCH format.After the UE 106 goes to in-synchronization state, the UE 106 mayattempt cell reselection and send a RACH message on the uplink. Thesignal conditions may be such that the RACH response and the SIBtransmissions are decodable by the UE 106. Further, a Format 1C codewordmay have lower error protection, minimum power boost, and subcarriermapping that achieves minimum frequency-time diversity resulting in thelimiting behavior. Alternately, the UE 106 may use any other typicalcontrol channel format aimed at characterizing the typical behavior.

In one example, the UE 106 may form BLER estimates for five subframesseparated by 20 ms in a 100 ms processing window for the purpose ofin-synchronization evaluation. For a subframe for which the PDCCH BLERis being estimated, the UE 106 may assume that a PDCCH Format 1C payloadof ˜31 bits (for 10 MHz operation) is being transmitted in the controlregion on the first three OFDM symbols in the subframe, starting thefirst CCE in the common search space at an aggregation level of 2. TheUE 106 may identify the time-frequency resource element groups on whichthe codeword gets mapped and calculate the reference signal SINR forthose resource element groups. The UE 106 may use channel stateinformation to determine the BLER for that subframe.

FIG. 6 illustrates, in a flowchart, one embodiment of a method 600 ofdetermining whether a radio link is in—synchronization. The UE 106 maymaintain a radio link with a base station (Block 602). The UE 106 maymap channel state information function for the radio link based on thesubcarrier over a specified bandwidth (Block 604). The UE 106 may setthe recovery range based upon a payload parameter, such as controlchannel type (Block 606). The control channel type may be a specifictransmission format, sub-carrier mapping, transmit antennaconfiguration, power boost, or other parameters. The transmission formatmay be an error correcting code type, payload size, code rate, blocksize, modulation type, or other formats. The error correcting code typemay be a convolution code, block code, turbo-code, or other codes. TheUE 106 may estimate the metric for the radio link based on the channelstate information using a format best suited for determining if theradio link recovery is about to occur, or recovery format (Block 608).The metric may be a block error rate, a mean mutual information per bit,average signal to noise ratio, channel capacity, or other metric. If themetric is within the recovery range (Block 610), the UE 106 maydesignate the radio link as having an in synchronization event (Block612).

Embodiments within the scope of the present invention may also includecomputer-readable media for carrying or having computer-executableinstructions or data structures stored thereon. Such computer-readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium which can be used to carryor store desired program code means in the form of computer-executableinstructions or data structures. When information is transferred orprovided over a network or another communications connection (eitherhardwired, wireless, or combination thereof) to a computer, the computerproperly views the connection as a computer-readable medium. Thus, anysuch connection is properly termed a computer-readable medium.Combinations of the above should also be included within the scope ofthe computer-readable media.

Embodiments may also be practiced in distributed computing environmentswhere tasks are performed by local and remote processing devices thatare linked (either by hardwired links, wireless links, or by acombination thereof) through a communications network.

Computer-executable instructions include, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing device to perform a certain function orgroup of functions. Computer-executable instructions also includeprogram modules that are executed by computers in stand-alone or networkenvironments. Generally, program modules include routines, programs,objects, components, and data structures, etc. that perform particulartasks or implement particular abstract data types. Computer-executableinstructions, associated data structures, and program modules representexamples of the program code means for executing steps of the methodsdisclosed herein. The particular sequence of such executableinstructions or associated data structures represents examples ofcorresponding acts for implementing the functions described in suchsteps.

Although the above description may contain specific details, they shouldnot be construed as limiting the claims in any way. Other configurationsof the described embodiments of the invention are part of the scope ofthis invention. For example, the principles of the invention may beapplied to each individual user where each user may individually deploysuch a system. This enables each user to utilize the benefits of theinvention even if any one of the large number of possible applicationsdo not need the functionality described herein. In other words, theremay be multiple instances of the electronic devices each processing thecontent in various possible ways. It does not necessarily need to be onesystem used by all end users. Accordingly, the appended claims and theirlegal equivalents should only define the invention, rather than anyspecific examples given.

1-20. (canceled)
 21. A method for a telecommunications apparatus todetect a status of a radio link, the method comprising: receiving, bythe telecommunications apparatus, a reference signal transmitted from abase station; assuming, by the telecommunications apparatus, atransmission of a codeword of a first payload type from the basestation; and determining, by the telecommunications apparatus, asynchronization status based on the received reference signal and theassumed transmission of the codeword of the first payload type from thebase station.
 22. The method of claim 21 further comprising: estimatinga block error rate applicable to the assumed codeword of the firstpayload type based on the reference signal; and determining thesynchronization status from the estimated block error rate.
 23. Themethod of claim 21 further comprising: estimating, from the receivedreference signal, a metric of at least one of a block error rate, a meanmutual information per bit, average signal to noise ratio, and channelcapacity using a failure format; and determining if the radio link hasan out-of-synchronization event if the metric is within a failure range.24. The method of claim 23 further comprising: setting the failure rangebased upon at least one payload parameter.
 25. The method of claim 24wherein the payload parameter is at least one of a specific transmissionformat, sub-carrier mapping, transmit antenna configuration, aggregationlevel, and power boost.
 26. The method of claim 23 further comprising:determining the out-of-synchronization event for the radio link if asignal strength is below a synchronization check threshold.
 27. Themethod of claim 21 further comprising: estimating, from the receivedreference signal, a metric of at least one of a block error rate, a meanmutual information per bit, average signal to noise ratio, and channelcapacity using a recovery format; and determining if the radio link hasan in synchronization event if the metric is within a recovery range.28. The method of claim 27 further comprising: setting the recoveryrange based upon at least one payload parameter.
 29. The method of claim21 further comprising: processing the received reference signal over aspecified bandwidth.
 30. The method of claim 21 wherein the referencesignal corresponds to a cell-specific reference signal.
 31. The methodof claim 22 further comprising: estimating, from the received referencesignal, an average block error rate over an out-of-synchronizationprocessing duration; and determining if the radio link has anout-of-synchronization event if the average block error rate exceeds afailure threshold.
 32. The method of claim 25 wherein the payloadcorresponds to a physical downlink control channel format 1A.
 33. Themethod of claim 22 further comprising: estimating from the receivedreference signal an average block error rate over an in-synchronizationprocessing duration; and determining if the radio link has an insynchronization event if the average block error rate is below arecovery threshold.
 34. The method of claim 28 wherein the payloadparameter is at least one of a specific transmission format, sub-carriermapping, transmit antenna configuration, aggregation level, and powerboost.
 35. The method of claim 34 wherein the payload corresponds to aphysical downlink control channel format 1C.
 36. The method of claim 25wherein the specific transmission format is one of a downlink controlinformation 1A and a downlink control information 1C.
 37. The method ofclaim 22 wherein the block error rate applicable to the assumed codewordof the first payload type is assumed regardless of whether a codeword ofthe first payload type is actually transmitted by the base station. 38.The method of claim 22 wherein estimating the block error rateapplicable to the assumed codeword of the first payload type based onthe reference signal further comprises estimating the block error ratewithout decoding the assumed codeword.
 39. The method of claim 21wherein the first payload type is at least one of a control channelelement size, a resource element group size, a size of subcarriersaggregated, a payload size, a subcarrier mapping, a power boost relativeto the reference signal, a specific transmission format, a transmitantenna configuration, and a control region size.